The first thing I thought of concerning Sparkle is customer support. If we design a site using Sparkle, and our customers visit the site, what sort of experience will they have if they don’t have Windows Vista? Imagine a Mac user on Safari. Or a Linux user? They will have no way to view the content. The app will just break.

Alternately, you would have to point those users (XP, Mac, Linux) to a special download of an altered or limited version of Avalon made for those platforms. It seems that downloading something with that large of a graphic framework would not be as simple as a Flash Player download.

You would download probably a 60MB+ file (just a guess) and then after install have to reboot before you can view the content. That’s a journey that nearly any non-computer savvy customer will not be willing to take. And most companies, large or small, would be hesitant to help them through.

Right now we can do a LOT with the Flash Player using the tools Macromedia provides, and a new install takes seconds, and without a reboot if users don’t happen to have it. In my mind, Sparkle’s features will be the best thing ever to hit application development for Windows Vista and future platforms. But for the web, Sparkle has a lot of limitations compared to Flash’s cross-platform ubiquity.